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Biomedical subjects

P Sloan

Publications and source records attributed to P Sloan.

At least 19 recordsLinked to original sources
PubMed2001

Immunolocalisation of cartilage-derived retinoic acid-sensitive protein in pleomorphic adenoma of the parotid salivary gland.

Pleomorphic adenoma of the parotid salivary glands often contains chondroid elements and may exhibit cartilaginous and osseous differentiation, although the latter is extremely rare. Twenty-nine pleomorphic adenomas (PAs) of the parotid gland were examined immunohistochemically for the distribution of cartilage-derived retinoic acid-sensitive protein (CD-RAP), a recently described marker of chondrocytes, which may be important in the morphogenesis and development of the salivary gland. In the normal parotid gland, the ductal cells expressed CD-RAP, but not the myoepithelial cells. In the pleomorphic salivary adenomas, the duct-like cells, but not the myoepithelial cells, expressed CD-RAP. Since many authorities consider myoepithelial cells to be the source of the chondroid matrix, it is surprising that these cells do not express the chondrocytic marker, CD-RAP. Putative neoplastic myoepithelium in the pleomorphic adenoma and some cells in the myxochondroid areas expressed S-100 and calponin.

Adenoma, Pleomorphic↗
PubMed2001

The effect of streptozotocin-induced experimental diabetes mellitus on calvarial defect healing and bone turnover in the rat.

Tooth socket healing is delayed in diabetes mellitus due to impairment of the healing process. One reason for the poor healing may be an abnormal vascular response. The object of our experiments was to study the effect of diabetes mellitus on bone healing using a calvarial wound. Streptozotocin, injected intraperitoneally, was used to induce diabetes in rats. Both insulin-treated, streptozotocin-dosed animals and normal rats were used as controls. Bone formation was measured in the diabetic femur and tibia, and healing of bone defects by guided tissue regeneration was assessed. Cancellous bone volume and bone formation in the femur were greatly reduced in the diabetic model, indicating either a defect of mineralization or osteoid formation. The length, dry weight, ash weight and calcium content of the tibiae of diabetic rats were significantly less than those of the control groups. In a second experiment, a sterile wound was made in the calvaria of diabetic rats, and covered internally and externally with Gore-Tex membrane. Exuberant formation of a primitive bone was evident, with little evidence of osteoclastic resorption of the necrosed bone ends. This was despite the impaired bone formation observed in the long bones in the first experiment.

Animals↗
PubMed2001

Survey of clinical members of the association of dental implantology in the United Kingdom: Part I. Levels of activity and experience in oral implantology.

The aims of this survey were to 1) determine recruitment rates of active oral implantologists, 2) establish the proportion of participants who carry out the surgical aspects of implantology, 3) quantify levels of surgical activity, 4) determine the type of qualifications held by this sample, and 5) identify the location of implant activity of clinical members of the Association of Dental Implantology (UK). Questionnaires were mailed to the 408 members of the ADI registered as clinical members of the ADI; data were collected between July 1998 and May 1999. A response rate of 66.9% was achieved. Active members increased markedly from 1985 to 1995. Surgical activity and clinical experience varied widely: 32.9% had placed 100 to 499 implants, 29.8% had inserted 1 to 49 implants, and 4.3% had inserted > or = 2,000 implants. The total number of implants inserted by this sample could only be estimated (between 51,000 and 90,000). The majority of this sample possessed postgraduate qualifications, although only 2.6% possessed a degree in oral implantology. The data from this sample indicated that the recruitment rate to the ADI (UK) increased markedly between 1985 to 1995, after which it seems to have slowed down. Most of the respondents were involved in the surgical aspects of implantology, although the level of surgical involvement varied widely. The low incidence of postgraduate degrees in implantology might reflect the relatively limited opportunities currently available for such training in the UK.

Clinical Competence↗
PubMed2001

A survey of clinical members of the association of dental implantology in the United Kingdom. Part II. The use of augmentation materials in dental implant surgery.

The following were the objectives of Part II of the survey: (1) to determine which augmentation materials were used by respondents, (2) to elicit which factors influenced the choice of augmentation materials, (3) to establish the perceived levels of evidence that support augmentation materials, and (4) to ascertain the clinical applications of particulate augmentation materials (autografts, allografts, and alloplasts). Autogenous bone and demineralized freeze-dried bone are used most frequently. The majority of respondents involved in bone augmentation indicated that alloplasts and allografts should be used to correct small defects or as volume expanders in conjunction with autogenous bone. Research publications and personal clinical observation mainly determine the choice of an augmentation material. Of the clinicians who preferred to use autogenous bone, 26.3% thought that there was at least one randomized controlled trial with histological evidence supporting its use in oral implantology. In comparison, 30% of demineralized freeze-dried bone users thought that there was at least one randomized controlled trial with histological evidence supporting its use. Collected bone debris is currently used for the correction of bone dehiscences and fenestrations around endosseous dental implants in the simultaneous implant-placement augmentation technique. There is a pressing requirement for the two most commonly used augmentation materials (autogenous bone and demineralized freeze-dried bone) to be evaluated by accepted scientific protocols. Although regard for autogenous bone as an augmentation material is high, its use in the form of collected bone debris seems to be limited at present.

Alveolar Ridge Augmentation↗
PubMed2001

A survey of clinical members of the Association of Dental Implantology in the United Kingdom. Part III. The use of augmentation techniques in dental implant surgery.

The aims of the survey were to: (1) determine the use of the staged and simultaneous augmentation techniques; (2) determine trends in the use of barrier membranes; (3) establish the perceived reliability of techniques used to monitor implants that have undergone simultaneous augmentation; and (4) assess the use of biopsy techniques to confirm the histologic outcome of bone augmentation. One hundred seventy-two respondents replied to this section of the survey and indicated that the "staged" and "simultaneous" augmentation techniques were used in roughly equal numbers during 1997, and a wide range of complications was reported with the latter. The majority used barrier membranes to correct defects of between 5 and 10 mm3, and resorbable membranes were preferred. With regard to clinical techniques used to monitor augmented implants, these were mainly considered to be "adequate" or "poor." Tissue biopsy was recognized as an important tool for determining the outcome of augmentation procedures but was rarely used. The use of resorbable membranes is likely to increase. The diagnostic tools currently used to monitor augmented implants are considered to have limited reliability, and they should be evaluated by prospective, comparative studies. More widespread use of biopsy techniques might help establish an evidence base for the histologic outcome of augmentation materials and techniques.

Absorbable Implants↗
PubMed2000

Impact factor.

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Bibliometrics↗
PubMed2000

Laser-tissue interaction with a continuous wave 3-mcm fibre laser: preliminary studies with soft tissue.

BACKGROUND AND OBJECTIVE: Lasers operating at wavelengths in the mid-infrared region have become increasingly popular for applications in areas of surgery and medicine. Advances in fibre laser technology have introduced a highly efficient, compact, diode-pumped source operating at around the 3-mcm wavelength. This study examines the effects of this recently developed laser on soft biological tissue. STUDY DESIGN/MATERIALS AND METHODS: Chicken breast and liver tissue samples were exposed to 800 mW continuous wave laser power, at a wavelength of 2.71 mcm, with incident spot sizes of around 150 mcm. Samples were inspected grossly immediately after laser irradiation and also prepared for histologic processing. RESULTS: After irradiation, visual assessment of changes at sample surfaces indicated a region of thermally affected tissue surrounding the ablation crater. This region was observed to grow in size to around 1.0 mm in diameter after 3 seconds of laser exposure at 800 mW. An ablation velocity of 0.80 mm.s(-1) was determined in chicken breast for the same incident laser parameters. Analysis of samples irradiated at 800 mW and processed for histology revealed minimal damage at hole boundaries and no signs of char formation, providing incident exposure times were restricted to below around 0. 5 seconds. CONCLUSION: This fibre laser source has demonstrated its potential to fulfil medical applications, enabling accurate, precise tissue removal to proceed at a rapid ablation rate. The efficiency and small size of the laser are attractive features.

Animals↗
PubMed2000

Increasing incidence of oral cancer amongst young persons: what is the aetiology?

The reasons for an increasing incidence of oral cancer, particularly amongst younger persons is unclear. It has been hypothesised either to be a result of an increase in exposure to known risk factors amongst certain groups in the community, or to be due to new aetiological agents. Prior to conducting large expensive population-based studies, it seems appropriate to conduct initial smaller-scale surveys to assess evidence for each of these two hypotheses. This survey of young persons with oral cancer suggest that most are exposed to traditional risk factors of tobacco smoking, drinking alcohol and a low consumption of fruit and vegetables.

Adolescent↗
PubMed2000

Oral lichenoid lesions after hepatitis B vaccination.

The association of mucocutaneous lichen planus and chronic liver disease is widely recognized. The hepatitis B and C viruses have been implicated as being important in this association, although their exact role remains unclear. Recently, lichenoid lesions of the skin after a hepatitis B vaccination have also been reported. In this case, a woman of Southeast Asian origin had lichenoid lesions affecting the oral mucous membranes develop after she was vaccinated against hepatitis B. The lesions appeared 3 weeks after the administration of the third dose of the vaccine and persisted for about 1 year. As the use of the hepatitis B vaccine becomes more widespread, more such cases can be expected to be encountered.

Administration, Topical↗
PubMed2000

Re-expression of procollagen type IIA in oral squamous cell carcinoma.

There are two forms of procollagen type II (IIA and IIB), both of which are expressed during chondrogenesis. Procollagen type IIA also is present at sites of developmental epithelial-mesenchymal interaction. Malignant transformation is associated with disturbed epithelial-mesenchymal interaction and the reappearance of fetal characteristics. This study aims to determine whether or not procollagen type IIA is re-expressed in oral squamous cell carcinoma (OSCC). Immunoperoxidase techniques were applied to frozen and paraffin sections of OSCC (n = 30) and normal oral mucosa (n = 5). In the carcinoma group, strong cytoplasmic staining for collagen type II was present (25/30). Staining was weak or absent in the stroma, and absent from the normal oral mucosa. Frozen sections from 10 of the carcinoma cases which showed positive staining were incubated with antibodies specific for procollagen type IIA and visualised using immunofluorescence. Staining was evident in each case and was particularly strong in the region of the basement membrane. Slot-blot analysis of collagen extracts from OSCC supported the immunohistochemical findings. We conclude, therefore, that procollagen type IIA is re-expressed in OSCC.

Carcinoma, Squamous Cell↗
PubMed1999

A survey of oral implantology teaching in the university dental hospitals and schools of the United Kingdom and Eire.

AIM: To provide an overview of the currently available academic teaching and clinical training in oral implantology at the university dental schools and hospitals of the United Kingdom and Eire. METHOD: A questionnaire was sent to the dean or director of dental studies and forwarded to the respective units involved in the academic teaching and clinical training of oral implantology. The setting was the university dental hospitals, and dental schools of the UK and Eire. Information was collected between July 1997 and March 1999. The main outcome measures were course availability, duration and emphasis for undergraduate and postgraduate study in the clinical discipline of oral implantology. The units or departments responsible for training and teaching were identified and formal degree courses were distinguished from non-degree courses. RESULTS: All institutions replied to the survey. All university dental schools provide undergraduate training in oral implantology in accordance with the guidelines provided by the General Dental Council. However, the courses vary with regard to the departments involved and the level of student participation. Thirteen centres provide informal postgraduate training with the duration ranging from one to eighteen days. Just eight centres provide formal academic graduate training based on oral implantology leading to recognised degrees. CONCLUSION: All university dental schools provide undergraduate teaching in oral implantology. Most centres also provide informal postgraduate training based on oral implantology. However, opportunities for academic graduate training, leading to recognised qualifications in this subject, appear limited at present.

Certification↗
PubMed1999

Epidural hematoma following epidural catheter placement in a patient with chronic renal failure.

PURPOSE: We report a case of epidural hematoma in a surgical patient with chronic renal failure who received an epidural catheter for postoperative analgesia. Symptoms of epidural hematoma occurred about 60 hr after epidural catheter placement. CLINICAL FEATURES: A 58-yr-old woman with a history of chronic renal failure was admitted for elective abdominal cancer surgery. Preoperative laboratory values revealed anemia, hematocrit 26%, and normal platelet, PT and PTT values. General anesthesia was administered for surgery, along with epidural catheter placement for postoperative analgesia. Following uneventful surgery, the patient completed an uneventful postoperative course for 48 hr. Then, the onset of severe low back pain, accompanied by motor and sensory deficits in the lower extremities, alerted the anesthesia team to the development of an epidural hematoma extending from T12 to L2 with spinal cord compression. Emergency decompressive laminectomy resulted in recovery of moderate neurologic function. CONCLUSIONS: We report the first case of epidural hematoma formation in a surgical patient with chronic renal failure (CRF) and epidural postoperative analgesia. The only risk factor for the development of epidural hematoma was a history of CRF High-risk patients should be monitored closely for early signs of cord compression such as severe back pain, motor or sensory deficits. An opioid or opioid/local anesthetic epidural solution, rather than local anesthetic infusion alone, may allow continuous monitoring of neurological function and be a prudent choice in high-risk patients. If spinal hematoma is suspected, immediate MRI or CT scan should be done and decompressive laminectomy performed without delay.

Analgesia, Epidural↗
PubMed1999

Expression of cartilage-derived retinoic acid-sensitive protein during healing of the rat tooth-extraction socket.

Cartilage-derived retinoic acid sensitive protein (CD-RAP) is a recently described, cartilage-specific protein. During early healing of the tooth-extraction socket, cells express both chondrogenic and osteogenic cell markers, but no cartilage is formed. Cartilaginous collagen type II protein, a major constituent of hyaline cartilage, has not been detected in the healing socket, although type IX collagen, which coats these fibres, has been detected transiently in early socket healing. This study investigated the spatial and temporal expression of CD-RAP and various osteoblast cell markers, i.e., alkaline phosphatase, osteopontin, osteonectin and osteocalcin, during healing. Immunolocalization of these proteins was determined in the rat tooth socket at 3, 4, 5, 6, 7, 8, 10 and 14 days after extraction. CD-RAP was expressed by preosteoblast cells maximally at 6, 7, and 8 days after extraction. Fully differentiated osteoblasts expressed osteocalcin, a specific osteoblast marker. Preosteoblasts and fibroblasts did not express osteocalcin. On double immunofluorescent staining, some preosteoblasts coexpressed CD-RAP (indicative of chondrogenic differentiation), and either alkaline phosphatase or osteopontin (markers of osteogenic stem-cell maturation). There was no colocalization between osteopontin and osteonectin. CD-RAP was unique amongst the cell markers used in that it was expressed by preosteoblasts, but not by osteoblasts lining the newly formed trabeculae. CD-RAP may have an important role in osteoblast cell differentiation during bone healing.

Alkaline Phosphatase↗
PubMed1999

Bizarre parosteal osteochondromatous proliferation in the anterior maxilla: report of a case.

Bizarre parosteal osteochondromatous proliferations are a rare subgroup of the osteochondromatous lesions. They must be differentiated from reactive osteochondromatous proliferations, low grade parosteal osteogenic sarcoma, and chondrosarcoma. Their recognition is important from the point of view of management, which should be by simple excision. This article describes a case of bizarre parosteal osteochondromatous proliferation in a 2-year-old child; the lesion developed in the anterior maxilla, a previously unreported site.

Child, Preschool↗
PubMed1999

Loss-of-function mutations in the cathepsin C gene result in periodontal disease and palmoplantar keratosis.

Papillon-Lefèvre syndrome, or keratosis palmoplantaris with periodontopathia (PLS, MIM 245000), is an autosomal recessive disorder that is mainly ascertained by dentists because of the severe periodontitis that afflicts patients. Both the deciduous and permanent dentitions are affected, resulting in premature tooth loss. Palmoplantar keratosis, varying from mild psoriasiform scaly skin to overt hyperkeratosis, typically develops within the first three years of life. Keratosis also affects other sites such as elbows and knees. Most PLS patients display both periodontitis and hyperkeratosis. Some patients have only palmoplantar keratosis or periodontitis, and in rare individuals the periodontitis is mild and of late onset. The PLS locus has been mapped to chromosome 11q14-q21 (refs 7, 8, 9). Using homozygosity mapping in eight small consanguineous families, we have narrowed the candidate region to a 1.2-cM interval between D11S4082 and D11S931. The gene (CTSC) encoding the lysosomal protease cathepsin C (or dipeptidyl aminopeptidase I) lies within this interval. We defined the genomic structure of CTSC and found mutations in all eight families. In two of these families we used a functional assay to demonstrate an almost total loss of cathepsin C activity in PLS patients and reduced activity in obligate carriers.

Aggressive Periodontitis↗